[amsat-bb] Working FOX-1A

E.Mike McCardel mccardelm at gmail.com
Sat Jul 4 15:08:22 UTC 2015

I am a bit disturbed that Dave Jordan's fine article on FOX-1A in
July's QST is being misrepresented by the quote that is purely out of
context. Anyone who read the full article can clearly see that Dave is
NOT advocating using half duplex to communicate with FOX-1A. The full
text of the excerpt reads "With a minimum power output of 400mW, Fox1A
should be easy to work with an ordinary VHF/UHF FM  handheld
transceiver and a dual-band handheld Yagi antenna. Most VHF/UHF
handhelds can only communicate in "half duplex." This means they
cannot receive simultaneously while transmitting. A half-duplex rig
ill be adequate for Fox satellites, but a "full duplex" transceiver is
even better. A full duplex transceiver receives and transmits at the
same time. This allows you to monitor the quality of your signal
through the satellite so that you can make antenna and frequency
adjustments as needed."

As I read this it seems the author makes the statement as to why full
duplex is superior and preferred over half duplex. A nice teachable
moment for the newbie to understand that while FOX-1A and other FM
satellites can in fact be worked half duplex it is best understand why
full duplex is the preferred method. My first contacts were half
duplex and I quickly learned that full duplex was not only preferred
but is the acceptable way to communicate through any satellite. At the
time I got started I was influenced by an article on the web titled
"Work FM Satellites with your HT!" advocating that all I needed was a
single handheld and a tape measure antenna. I notice that the article
has been since updated to include "Ideally, we should be working the
satellites in full duplex mode, where we can simultaneously listen to
the downlink as we are transmitting." Thank you for clarifying this.
However, I am confused,  especially seeing this recent criticism, that
the article just mentiend continues the previous sentence with "
Although this method is preferred, it is not mandatory:"

I commend Dave for his article and efforts to keep us all informed and educated.


E. Michael McCardel, KC8YLD
V.P. for Educational Relations, AMSAT-NA

Have you donated to get your Fox-1 Challenge Coin Yet?

On Sat, Jul 4, 2015 at 1:18 AM, Clint Bradford <clintbradford at mac.com> wrote:
> I was startled reading AA4KN's proclamation in his July, 2015 QST article
> that " ... a half-duplex rig will be adequate for the Fox satellites, but a "full
> duplex" transceiver is even better ... "
> Gawd, if I had published that, I would have crosses burning on my front lawn.
> Confirming we should still be teaching that "Working FOX-1A in true, full
> duplex mode is preferred ... " - and suggesting methods to accomplish just
> that?
> Clint K6LCS
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